1. Field of the Invention
Embodiments of the present invention relate to computer programs, methods, and systems for hybrid CT attenuation correction. More particularly, various embodiments of the invention relate to a computer program, method, and system for attenuation correction that utilize an ordered subset expectation maximization-bayesian algorithm to facilitate hybrid CT attenuation correction.
2. Description of the Related Art
Radionuclide myocardial perfusion imaging (MPI) is a popular method to assess patients with known or suspected coronary artery disease (CAD). Thallium-201 or Technetium-99m are generally utilized within single photon emission computed tomography (SPECT) to perform MPI. However, technological advances have rendered the use of myocardial perfusion positron emission tomography (PET) with NH3-Ammonia or Rubidium-82 more desirable in various situations than SPECT. Specifically, PET generally provides higher spatial resolution, greater counting efficiencies, and more robust scatter and attenuation correction than that available with SPECT.
PET methods require attenuation correction for the effects of patient specific photon attenuation. Patient specific photon attenuation is the result of a radiopharmaceutical that is injected into a patient to facilitate MPI. PET attenuation methods include utilizing transmission data acquired from a scanner, such as PET source (dedicated PET) or an X-ray source (PET/CT), to correct emission data for the effects of patient specific attenuation.
Although methods are known to facilitate PET attenuation correction, these known methods often provide poor or insufficient transmission counts for reconstruction, allow misregistration and resolution mismatch between transmission and emission data, and fail to correct for the effects of metallic implant artifacts or patient respiratory motion.